Hi there!
I'm trying to find out the exact size of the "Bank of Ireland" notes around the period of 1916 (series E) and "The National Bank" (series B). Similar British notes of the time appear to be around 135mm x 75mm but I can't confirm the size anywhere of the Irish notes. If anyone can help that wold be great!

The sizes for the large sized notes varied slightly. I have the following measurements to hand. The Bank of Ireland notes were bigger than those of other banks by a small margin. I think the sizes of the others depended on the printers. Bank of Ireland printed its own notes in Dublin, the other banks' notes were printed by commercial printers inEngland, as far as I recall.

Thanks for that, I didn't think the notes were quite that large!
Can you tell me if the 1918 series from Bank of Ireland were smaller? The reason I ask is that I will be reproducing bank notes for use in a film and the 228mm x 126mm size seems very cumbersome to use. The £1 notes and 10 shilling notes of that period (approx 150 x 80mm) are closer to what I was imagining.

The 1918-1921 Bank of Ireland notes were smaller, approximately 150x100mm, though the higher denominations were still large sized. these small sized BoI notes were still printed on handmade paper, so were slightly irregular sized with rough edges.

Notes of the other banks in this era 1918-1920, National Bank, for example became smaller also, approximately 145x85mm. These notes were sheet printed, thus with regular edges when cut.